Won't breed for me! Help!

I have a pair of PI Chahoua that have bred just once in the past, but for the life of me i cannot get them to be "interested" in one another anymore. I have tried for about 9 months and they seem to just want to be friends. My female weighs more @ approx. 59 grams and is just over 2.5 years old, and my Male is a bit smaller @ approx. 54 grams and is about 3 years old +/-.
They are housed in a bigger than average terrarium (24x24x18), but utilize every inch and definately have chances to breed TONS, but never do. i am really bummed about this and was wondering if any of you can help me figure out a way to make the magic happen again. I appreciate all responses! Thanks.